valves and the boilers. If repairs are needed, see that they are made promptly. In making a quarterly check on the blowoff valves, do not overlook the insulation, bearing in mind that it should be kept dry. Another item is the discharge piping leaking from the valves. Make sure the discharge piping is not mounted so rigidly that proper expansion and contraction are affected.
Keep SAFETY VALVES (fig. 2-4) in top working order. At regular intervals, depending upon operating conditions, the safety valves must be lifted manually. At least once each year the valves should be tested by raising steam pressure to popping pressure of the respective valve. If safety valves function improperly, promptly report the matter to your immediate supervisor. For detailed information on the maintenance of safety valves, refer to manufacturer's manual.
With injectors, little maintenance is required. At times you will have to reseat the overflow and ring valve. Lime deposits also can reduce the operation by closing down the size of the combining and delivery tubes. A good way to remove lime deposits is to place the injector in a tube of muriatic acid for several hours.
To clean the injector, remove the bottom plug (fig. 2-5). The delivery tube and ring valve drop out. Examine and clean all passages and holes. After cleaning, replace them in the plug (which acts as a guide) and screw tightly in place.
Once each month, see that steam traps are tested for correct operation. Methods used in testing steam traps (such as the test valve method, the glove test method, etc.) are discussed in another section of this training manual.
Once a year, or more often if required, dismantle and clean all traps. Inspect for the following:
1. The accumulation of foreign matter
2. Plugging of orifices, valves, and vents
3. Cracked, corroded, broken, loose, worn, or defective parts
4. The excessive wear, grooving, and wire drawing of valves and seats
5. Defective bellows, buckets, or floats
6. Leaky vessels and pipes
7. Defective bypass valves
Repair or replace defective parts as required following yearly inspection. Replace or repair all
Figure 2-4. - A typical spring-loaded safety valve.
Figure 2-5. - A cross-sectional view of an injector.Continue Reading